A vehicle air bag system typically comprises an air bag module which is secured to a structural part of the vehicle. The module generally comprises (i) a container for a folded air bag, and (ii) a gas generator (also known as in inflator) disposed either partially or wholly within the container, and adapted to generate gases to deploy the air bag at the onset of a collision. Generally, the container comprises a reaction device adapted to be connected to the folded air bag and to a structural part of the vehicle, and a cover attached to the reaction device. In certain air bag module constructions, the reaction device comprises a can, and both the inflator and the folded air bag are disposed within a cavity formed in the can. In other types of air bag module constructions, the reaction device comprises a plate-like member. The cover and the reaction member in such constructions cooperate to define the air bag cavity, and the inflator is disposed at least partially within the cavity formed by the plate and cover.
Regardless of the specific construction of the module, it is important to attach the air bag efficiently and securely to the reaction device. At the onset of a collision, when the inflator is ignited, gases are generated under relatively high pressures. Those gases are directed rapidly into the air bag to inflate the air bag within milliseconds of the onset of the collision. As the air bag is being inflated, significant forces are applied between the air bag and the reaction device. The fasteners between the air bag and the reaction device must be strong enough to withstand such forces, without allowing the air bag to become torn away from the reaction device during inflation.
Over the years, different ways for fastening air bags to reaction devices have been suggested. One well known technique is by means of bolts which extend through aligned openings in the air bag and the reaction device. Further, retainer bars can be bolted to the reaction device, with the air bag captured between the bars so that pressures along the air bag fabric are not localized. Examples of this construction are shown in U.S. Pat. No. 4,842,300.
Another way of securing an air bag to a reaction device is by means of specially formed plastic strip connected to the air bag and inserted into a clamp on the reaction device. An example of such a structure is shown in U.S. Pat. No. 4,111,457.
Still another way of connecting an air bag to a reaction device is by means of a specially constructed flange on the reaction device. The flange is adapted to clamp part of the air bag against another part of the reaction device. An example of such a device is shown in U.S. Pat. No. 3,778,085.
Still further examples of ways of securing an air bag to a reaction device comprise securing the air bag directly to a diffuser by means of a bracket and sheet metal screws (see e.g., U.S. Pat. No. 3,774,936) and special clamp and clamp bolts for securing an air bag to an outside of a manifold (see e.g., U.S. Pat. No. 3,642,303).
Finally, yet another way of connecting an air bag to a reaction device is by means of retainer rings and flanged nipples. An example of such a structure is shown in U.S. Pat. No. 2,834,606.
In the air bag art, there are continuing needs for new and useful fastening devices for attaching an air bag to a reaction device. Applicant believes such devices should be relatively simple and inexpensive to construct and simple to attach to air bags. Moreover, when the reaction device comprises a reaction can, applicant believes such a fastening device should enable the air bag to be connected to the inside of the reaction can. By attaching the air bag to the inside of the reaction can, the overall package size of the module is minimized and space is conserved. Conservation of space is becoming increasingly important in the air bag art, as the space allocated within the vehicle compartment for air bag modules decreases. Such decreases are due to overall reductions in automotive vehicle size, and to the limited space available in compact-sized vehicles.